Carbon solubility in a face centred cubic (fcc) Fe1-yNiyalloy lattice was analysed on the basis of statistical thermodynamics assuming negligible C—C interaction in the fcc Fe1-yNiylattice. The minimum carbon solubility was observed for values of y of ~ 0·6–0·7 and appeared to be ascribable to the minimum number of available interstitial sites for occupation by carbon atoms in the fcc Fe1-yNiylattice around this composition. Accordingly, the extent of stabilisation for carbon atoms in the fcc Fe1-yNiywas estimated to be a minimum around this composition. The observed variation for the carbon solubility and the extent of stabilisation of the carbon atoms in the fcc Fe1-yNiylattice with respect to the composition y appeared to be related to the stability of the ferromagnetic phase.MST/3251